The present invention relates to a mask, a method for manufacturing the same, and a method for manufacturing a semiconductor device. Particularly, the present invention is concerned with a mask for forming hole patterns such as contact holes, a method for manufacturing such a mask, and a semiconductor device manufacturing method including a hole forming step.
In manufacturing a semiconductor device, a semiconductor element and wiring are formed by repeating for example the steps of forming a certain film on a semiconductor substrate and performing a certain processing, e.g., etching, for the film. Before the processing, a resist pattern is formed on a certain substrate by a lithography step. Therefore, in the lithography step it is important to form a highly accurate resist pattern so that desired pattern size and shape are obtained by such a processing as etching.
With fine patterning, there is a tendency that a discrepancy in shape and size of the resist pattern relative to the shape and size of a design pattern becomes larger. In manufacturing a mask, therefore, an OPC (Optical Proximity effect Correction) processing is performed as a processing for correcting a design layout pattern so that there are obtained desired resist pattern shape and size. Usually, in the OPC processing, an edge of a design layout pattern is divided into plural edges and the thus-divided edges are each moved in parallel with an X- or Y-axis direction.
Since such an OPC processing is performed, particularly as the shape of an aperture pattern, there generally is employed a rectangular shape comprising pattern edges parallel to X and Y axes. In the case of the OPC processing or a biasing process, the size of an aperture pattern is varied by moving sides of the pattern in parallel with an X or Y axis.
As a design layout pattern correcting process there also is known a technology called Inverse Lithography Technology (Non-Patent Literature 1) in addition to the OPC processing. However, this technology involves the problem that an optimum mask pattern is very complicated in shape and that therefore the manufacture of a mask becomes more difficult. Accordingly, utility is enhanced by approximation using a simpler mask pattern shape.
[Non-Patent Literature 1]    Linyong Pang, et al.: “Validation of Inverse Lithography Technology (ILT) and Its Adaptive SRAF at Advanced Technology Nodes” Proc. Of SPIE., Vol. 6924, 69240T-1 (2008)